Roanoke Times
Copyright (c) 1995, Landmark Communications, Inc.
DATE: TUESDAY, February 7, 1995 TAG: 9502090050
SECTION: EXTRA PAGE: 3 EDITION: METRO
SOURCE: DAVID BUTLER
DATELINE: LENGTH: Medium
A: Improved definition television (IDTV) is an unfortunate name. It sounds like the latest buzzword invented by Madison Avenue to peddle high-end TV sets. However, this is definitely not the case.
IDTV takes today's television technology to its theoretical limit through a process known as progressive scan, or scan-line doubling. Scan lines are those pesky horizontal gaps in the picture that become all too obvious on larger screen sizes. With IDTV, the scan lines virtually disappear. This means that an IDTV picture looks nearly as good on a large-screen TV as it does on a 19-inch model!
If IDTV is like getting a new pair of glasses, HDTV will be like getting a new pair of eyes! HDTV represents a radical departure from the existing television standards developed in the '40s. Not only will the scan lines be invisible, but pictures will be broadcast at a much higher resolution - up to 1,050 lines. This is twice the maximum resolution supported by the existing standard and three to four times greater than the resolution typical of today's broadcast and cable television.
Furthermore, HDTV signals will be totally digital. HDTV receivers will be more like a computer than a conventional television set. This is hardly a coincidence. Emerging technologies such as interactive television, movies-on-demand, digital telephone lines and the information highway are already beginning to blur the lines that distinguish between computers, television and telecommunications.
In order to accommodate theatrical movies, HDTV screens will be nearly twice as wide as they are tall. The relationship between width and height is referred to as the aspect ratio. HDTV screens will have an aspect ratio of 16 to 9, a full one-third wider than conventional television. Even regular TV programs will eventually adopt the widescreen format.
Today, when movies are transferred to video tape for broadcast, they must be edited to fit TV's 4:3 aspect ratio. To satisfy home theater enthusiasts with big-screen televisions, more than 600 laser-disc and VHS titles have been released in "letterbox" format. Letterbox preserves the original aspect ratio by shrinking the picture to fit the width of the screen. This leaves a black border above and below the picture.
HDTV is still several years from mass-market availability. A group of seven manufacturers and research labs have formed a consortium called the Grand Alliance to finalize the design. The Federal Communications Commission is expected to rule on the Alliance's design in 1995. The 1996 Summer Olympics has been targeted for the first nationwide HDTV broadcast.
You don't have to wait for HDTV to get a widescreen television. During the past year, at least five manufacturers have introduced 16:9 televisions. Three models feature 34-inch diagonal picture tubes that measure nearly 21/2 feet wide! Rear projection models measure 50 inches to 58 inches diagonally. Note that for screens of the same height, a 16:9 diagonal is about 20 percent greater than a 4:3 diagonal.
Taking advantage of the unusual aspect ratio, most widescreen TVs feature Picture-Outside-Picture (POP). Here, three smaller still-frame pictures can be displayed to one side of the main picture, updated in sequence by a second tuner. Or you can view a selected channel live (similar to P-I-P). One model takes channel surfing to new heights. It can fill the screen with stills from up to twenty channels.
To receive a list of companies that manufacture widescreen and improved definition televisions and projection systems, please send $1.50 and a self-addressed envelope to David Butler F-448, Department TWN, 14713 Pleasant Hill Road, Charlotte, N.C. 28278-7927. The list includes toll-free phone numbers and a description of each company's products. You'll also receive information on scan-line doublers.
by CNB